Radon testing & mitigation in Northumberland County, PA
46% of basement tests here came back at or above 4 pCi/L, well above the statewide 37%. That means about one in 2 homes tested needs a fix.
Northumberland County radon test data
Share of basement tests ≥ 4 pCi/L
First floor: 16% of 1,932 tests ≥ 4 pCi/L, median 1.3
Source: computed 2026-10-11 from PA DEP's Radon Test Results, Sept 1986 - Current (data.pa.gov, public domain). Counts tests, not homes: repeat and post-mitigation tests are included. Only a test tells you your home's level.
1 DEP-certified firms have a business address in Northumberland County (0 offer mitigation), with 1 certified individuals between them. Get free quotes
Radon testing (1 firm)
Barclay, Gary
✓ PA DEP certifiedTestingWatsontown1 certified person
Barclay, Gary
✓ PA DEP certifiedTestingAddress
- 527 Fisher Dr, Watsontown, PA
- ✉ tallgaryb@yahoo.com
Certified individuals
- Barclay, Gary (testing #3501)
DEP cert IDs
Source: DEP list, retrieved 2026-10-11 · Claim, correct or remove this listing
Neighboring counties
Columbia (2 firms) · Dauphin (9 firms) · Juniata (0 firms) · Lycoming (2 firms) · Montour (0 firms) · Perry (1 firms) · Schuylkill (5 firms) · Snyder (2 firms) · Union (1 firms). Firms often serve across county lines.
Adjacency from U.S. Census Bureau county adjacency file.
Hiring a radon pro in Northumberland County: quick guide
With 46% of 10,034 basement tests at or above 4 pCi/L (above the 37% statewide share), Northumberland County has no locally based mitigation firm, so look at the neighboring counties listed below.
- Verify: check the firm in the PA DEP Radon Services Directory, ask for the DEP ID (25 Pa. Code Chapter 240), or call 800-237-2366.
- Typical cost: $786-$1,274 for a mitigation system, national range from the HomeAdvisor cost guide.
- Selling or buying: PA's seller disclosure form asks about known radon and past tests (49 Pa. Code § 35.335a).
Frequently asked questions
How many certified radon mitigation firms are in Northumberland County?
0 DEP-certified firms offering mitigation and 1 certified radon firms in total list a business address in Northumberland County (PA DEP lists dated 10/01/2026). Firms from neighboring counties may also serve the area.
What share of Northumberland County radon tests are high?
46% of 10,034 basement tests in PA DEP's records were at or above EPA's 4 pCi/L action level, with a median of 3.6 pCi/L.
How much does radon mitigation cost in Northumberland County?
We don't have county-specific price data. A national cost guide reports typical installs at $786-$1,274. Get written quotes from DEP-certified mitigators.